function setRemSize() {
    console.log(window.innerWidth);
    var deviceWidth = document.documentElement.clientWidth || window.innerWidth
    if (deviceWidth > 750) {
        deviceWidth = 750;
    }
    if (deviceWidth < 320) {
        deviceWidth = 320;
    }
    document.documentElement.style.fontSize = deviceWidth / 7.5 + 'px';
    document.querySelector("body").style.fontSize = 0.3 + "rem";
}
setRemSize()
window.onresize = function () {
    setRemSize();
}